Arrangement for receiving telegraph impulses



Jan. 8, 195,2 F. P. MASON ARRANEMENT FOR RECEIVING TELEGRAPH IMPULSES Filed Deo.

4 Sheets-Sheet l INVENTOR FEEDER/CK P. MASON A ORNEY Jan. 8, 1952 F. P. MASON ARRANGEMENT FOR RECEIVING TELEGRAPH IMPULSES 4 Sheets-Shee'c 2 Filed Dec. 13, 1946 FREDERICK lNvl-:NTQR

R MASON BYV ATTORNEY Jan. 8, 1952 F. P. MASON ARRANGEMENT FOR RECEIVING TELEGRAPH IMPULSES 4 Sheets-Sheet 3 Filed Dec. 13, 1946 lNvEN-roR FEEDER/CK P. MASON BY@ 2; ATTORNEY Jan. 8, 1952 F. P. MASON ARRANGEMENT F' OR RECEIVING TELEGRAPH IMPULSES 13, 194e 4 Sheets-Sheet 4V Filed Dec.

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INVENTOR cK P. MASON ATTORNEY Patented Jan. 8, 1952 vorriclz ARRANGEMENT FOR RECEIVING TELEGRAPH IMPULSES Frederick Percival Mason,

signor to Creed and Co don, England, a Britis Croydon, England, as-

mpany Limited, Croyh company Application December 13, 1946, Serial No.

In Great Britain March 24, 1939 section 1, Public Law 69o, August s, 1946 Patent expires March, .24, 1959 6 Claims. (Cl. 178-33) y This invention relates to a receiving arrangement for a printing telegraph system using combinations of impulses, each impulse consisting of one of two dilferent line conditions known as marking and spacing conditions existing during a denite interval of time.

When received, the impulses may have become distorted so that the appropriate condition, marking or spacing, does not persist throughout the whole of the time interval allotted thereto. In order to permit signals with the largest possible distortion to be received correctly, it is customary to read the sign-als, as shown by the posi-v tion of the armature of the receiving relay, in the middle of the interval allotted to each signal impulse. The theoretical duration of a printing telegraph signal impulse in the five-unit code is milliseconds at a speed of 50 bauds. VThe maximum theoretical margin of a receiving arrangement is limited in part by the relay transit time which may be 0.5 milliseconds and in part by the minimum duration of time during which it is possible to read the condition of the line, which may be 1.5 milliseconds. The line reading time thus causes a loss of margin of 71/% at 'a speed of 50 bauds, and this'is raised to SM10/z at a speed of 55 bauds.

The object of the present invention is to eliminate the time necessary for reading the nature of a signal impulse over and above thetransit time of the line relay.

The invention depends upon receiving a code combination by means which detects changes of condition in a line between successive elements of a code combination. The nature of the invention will be better understood from the following description taken in conjunction with the accompanying drawings, of which:

Figs. 1 to 4 illustrate different arrangements according to the invention as applied to receiving arrangements for the well known ve-unit code. In each of these arrangements instead of the usual arrangement in which the time devoted to each character is divided into ve intervals of equal duration each of which should be occupied by one of two different conditions, the time devoted' to each character is regarded as containing five intervals of equal duration, at the midpoint of each of which a change in condition of the line may take place. In these arrangements, the change of condition of the line may, owing t-o distortion, be displaced up to 10 milliseconds (for a speed of 50 bauds) in either early or late direction.

Referring to the drawings all the arrangements shown are of a generally similar character and are adapted for receipt of signals according to the start-stop system. In each arrangement a series of contacts CI-CG is provided, contact C6 of which is normally closed whilst contacts Cl-#C are adapted to be closed in succession by means of a rotating shaft started into rotation by the energisation of a magnet M. Each of the contacts Cl-CS remains closed for a period of 20 milliseconds at the middle of which the change in condition of the line should take place if the signals are undistorted. The changes in condition of the line are then stored on ve condensers Kl-K5, the charges on which are afterwards connected to the grids of three-electrode gas-filled tubes TI-T5 so that a discharge is initiated in such of the tubes as are'connected to condensers that have been charged. The anode circuits of these tubes are connected to a translating device. This device may com prise magnets or relays which carry out a trans lation of the combination of impulses by positioning a type carrier or like device in any well known manner. By like device is to be understood a device which instead of being itself a type carrier selects the position of a'type bar for actuation. For simplicity in what follows it will be assumed that a typewheel is positioned. Such typewheel may be positioned in accordance with the currents in the anode circuits of the tubes 'FI-T5 by means of the arrangements described and claimed in British Patent No. 499,209.

It must, however, be noted that the particular code combination of current or absence of current in the anode circuits of tubes Tl-T5 is not the same code combination of marking and spacing conditions as is received. It is thus necessary to alter the order of the characters on the typewheel positioned by the translating devicefrom that representing the ordinary five-unit code to that representing the new code.

Referring now to Fig. 1, this represents the simplest arrangement according to the invention. The line L over which signals are received is connected toa receiving relay A. The armature a of relay A is adapted to operate" between marking and spacing contacts m and s which are connected together and to ground. Whilst the armature a is resting on one of its contacts, a current passes from positive battery B6 through a resistance R3, the armature a and the contact to ground. As stated above, contacts C6 are normally closed so that when the armature a leaves itsmarking contact m in response to the start element `of asignal combination, the po in the anode circuit of the tube is energized and starts into rotation the shaft controlling the various contacts of the receiving arrangement. Contacts Cl-C5 are operated in sequenceand if, during the interval when any one 'of ,these contacts is closed, a transit of the armature c between marking and spacing or between spacing and marking contact occurs the potential of battery B6 is connected Athrough resistance R3, the rectifier MRS and the particular contacts that are closed to one side of one of the condensers Iii-K5, the other side of which is connected to ground. Contacts vC6 are opened, shortly after the commencement of rotation of the shaft and before the termination of the period of rotation of the shaft contacts Cl I5 are closed and the negative pole of a battery B1 is connected to the grid of tube T6 to extinguish the discharge therein. Immediately after the opening of `contacts C5 contacts CI'l--CIE are closed and connect one side of the condensers lil-K5 to the grids of the five tubes Tl-T5. These grids are normally connected over the grid leak resistance GRI- GRS to the negative pole of batteries BI-B5, so that the tubes are normally quiescent. When, however, the condensers are connected to thegrids of the tubes, those condensers that are charged will initiate a discharge in their corresponding tubes Vand the consequent currents in the anode circuits of Vthese tubes are utilised as described above. Contacts Cil and C15 are opened again bef-ore the shaft comes to rest and contacts Ci il to Cl l5 are closed. Leak resistances LI-LS are Aprovided in shunt to the respective condensers -Kl-K5 so that should the charge on any charged condenser not be completely discharged during Vits connection to the grid of lits corresponding tube, and should lit also not be recharged before its next connection to its corresponding grid the charge willleak away. The shaft controlling the contacts shown may start into rotation a further shaft controlling the printing action, or may close a contact to operate a printing magnet.

In the arrangement above described-any interference in the line or bounce of the relay armature that momentarily separates the xed and moving contacts of the receiving relay gives an eiect similar to the effect of a transit and such an arrangement could therefore only be used with a well adjusted relay connected to aline free from interference. This drawback is avoided in the arrangement shown in Fig?. In'ilhisl'arrangement the armature c of the vlinerelay A is operated by a coil connected in the line L, but is also wound with a coil 'o in which 'an impulse is generated at each movement of the armature.

As the direction of the gencratedimpulse current depends upon the direction of transit, rectiers MRI, MR2 are provided to obtain a posi-v tive impulse for either direction of transit ci the armature. In this arrangement the circuits an beso meer. there Papel ademen@ bf the armature does not provide sufficient energy to operate the gas-filled tubes 'FI-TE. In the modication shown in Fig. 3 the impulses generated in 'the coil b by the vrn'oven'ient of the armature-charge a condenser KE through a full wave rectiiier bridge MRB, MRS, MRM), MRI I. est the moment when the line relay contacts m or s close at the end of the armature travel the condenser K6 is connected through the armature and either the marking or spacing contacts m fand s and the rectier MRS to charge up the particular capacity Kl--K that is at the mo- ;ment connected. The effect of this arrangement is to reduce the elective line reading time to the time of discharge of the condenser K6. An inductance I fl may be connected in series with the condenser K6 and may be so proportioned that the discharge time of the condenser coincides Withhalf the period of the frequency to which condenser K6 and inductance L1 are tuned. This increases the amount of the charge transferred by virtue of the oscillatory action. In the arrangement shown in Fig. 4 the use of a line relay is obviated, but line L is connected to one diagonal of a full wave rectifier bridge MR, MRS, MRil MR? across the other diagonal of which is connected a resistance R. Any continuing condition of the line produces a unidirectional potential across Ril in opposition to the steady potential derived from a tapping on the potentiometer P across the battery B6. At those instants when the current in the line L passes through zero, this opposing potential becomes zero and the potentiometer P can supply a charge to whichever condenser K-Kis connected to the common circuit 8. This arrangement, however, is only adapted to receive double current signals.

Although in the above described 'arrangements a change in condition of the line results in a charge upon the corresponding condenser of the condensers Kl-K, it is clear that the circuits could equally well be arranged so that va charge on the condenser corresponded to an absence oi change or" condition in the line.

Whatis claimed is:

l. Receiving arrangement for .a printing telegraph system comprising ineans for registering consecutive changes in `the electrical condition of Aa signal line during reception over the line of a signal consisting of a series of consecutive elements each represented by a line condition, saidvmeans including a relay connected to said line and actuated by said changes, the relay vhaving an armature shifted between two contacts by each such change, a signal registering unit including a plurality oi registering elements, an operating circuit for said elements connected to the armature means for rendering the operating circuit efective only when the armature is out of engagement with said contacts, and means for connecting the operating circuit to said registering elements in succession during the periods of change-over from one signal element to the next; 'and means controlled by the registering means for producing corresponding simultaneous changes in the electrical conditions or" a plurality of Vprinting telegraph control lines.

2. An arrangement as claimed in claim l lin which the operating circuit includes a cur-rent source, and each registering element includes a device actuated by current from said source.. v

3. An arrangement as claimed in claim 2 in which said device is 'a condenser charged by said current.

4. An arrangement as claimed in claim 1 in which the means for rendering the operating circuit effective includes a current generating device actuated by movement of the armature.

5. Receiving arrangement for a printing telegraph system comprising means for registering consecutive changes in the electrical condition of a signal line during the reception over the line of a code signal consisting of a series of consecutive elements eachrepesented by a line condition, said means `voperable between successive elements of the code signal, said means including a relay connectedto said line and actuated by said changes. the relay having an armature shiftable between two contacts by each such change, a signal registering unit; and means for operating said unit to register a signal element when said armature is shiftedgsaid last named means including an operating circuit connected to said armature, means for rendering said circuit effective only when lthe armature is out of engagement with said contact-s, and means controlled byl said registering means for producing corresponding'simultaneous changes in the electrical conditions of a plurality of printing telegraph tacts.

FREDERICK PERCIVAL MASON.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name f Date 1,936,947 Morgenstern et al. Nov. 28, 1933 2,444,429 Cleeton July 6, 1948 FOREIGN PATENTS L Number Country Dato 499,209 Great Britain Jan. 16, 1939 

